“I do hope you’re following this,” the professor of neuroscience says to his students in the dizzying prologue of Lydia R. Diamond’s drama “Smart People.”

He might well wonder.

Prickly, provocative notions about race, class, prejudice, identity and sexuality ricochet like balls scattering across a pool table in this brainy but overstuffed drama, which opened on Thursday at Second Stage Theater in a slick production directed by Kenny Leon.

For all their fancy talk (and talk, and talk) about psychology, neurology and the ways in which racism pervades American culture — naturally a churning topic at the moment — the forces that bring these four characters together too often seem dictated more by the playwright’s desire to dive deeply into a swirling whirlpool of ideas rather than by natural circumstances. (Invoking the parlor game “Six Degrees of Kevin Bacon,” as Ms. Diamond does, feels like a bit of a fig leaf.)

In a scattered opening sequence, we hopscotch between introductions to the characters in their natural habitats, all in the vicinity of Harvard University, mostly in various states of frustration. Brian White, played with knife-sharp edges by Joshua Jackson, of Showtime’s “The Affair,” is a Harvard professor and “neuropsychiatrist” first seen berating his students for their incompetence.

Jackson Moore, given a brooding, forceful presence by Mahershala Ali, is an intern at Harvard Medical School who believes he’s often second-guessed — and worse — because of his skin color. We first meet him as he’s arguing with a superior, and paying the price for it. On the side, and somewhat implausibly given the hours interns famously work, he and some like-minded doctors have opened a clinic to help treat people without insurance (or good insurance).

Valerie Johnston (the excellent Tessa Thompson), the character most awkwardly integrated into the lives of the others, is an actress frustrated by the roles she’s offered, or not offered. In between auditions Valerie earns money on the side cleaning houses, but also working as Brian’s research assistant (contrivance alert). She also, in a sequence that seems unnecessary, goes door to door campaigning for Barack Obama, finding more often than not a chilly reception. (The action begins during Obama’s first presidential run, and concludes with his inauguration.)

Ginny Yang (a take-no-prisoners Anne Son) is a Harvard psychology professor, American by birth, but with both Japanese and Chinese ancestry. Radiating a brisk self-confidence that can come across as imperious, she’s first seen giving a presentation about her latest findings, which “debunk Western assumptions naming primary reasons for anxiety and depression in Asian-American women as familial.”

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From left, Tessa Thompson, Joshua Jackson, Mahershala Ali and Anne Son in Lydia R. Diamond’s drama.CreditSara Krulwich/The New York Times

Ginny and Brian meet very un-cute when they are early for a meeting of the Harvard “committee for the study of minority matriculation, retention and recruitment. Before the session starts Brian begins flirting, eventually obtaining Ginny’s phone number; their liaison is among the less believable developments, although it naturally gives rise to a comic scene in which Ginny mockingly acts out the stereotype of the sexually submissive Asian woman.

Valerie and Jackson meet, even more un-cutely, when she ends up in the emergency room after a stage accident. “Will I get to see a doctor?” she asks, the implication being that this young black man can only be a nurse. He smoothly disabuses her of that idea. He, meanwhile, assumes that she’s been roughed up by a lover, and she bridles: “What does a black woman have to do to convince you guys that she hasn’t been beaten?”

“Smart People” unfolds as a series of short scenes and monologues often spliced together and staged simultaneously. At times it feels like watching a tennis match, as you pivot from, say, Brian being rebuked over the phone for his abrasive attitude in class, to Ginny counseling a client with self-esteem issues.

The most controversial idea the play puts forth comes from Brian, who bluntly tells Valerie that his research aims to prove “that all whites are racist.” Ouch! “You didn’t know that?” Valerie fires back coolly.

Not unsurprisingly, his work proves incendiary. And in a scene that recalls the central set-to in Ayad Akhtar’s “Disgraced,” all four characters assemble for the first time for dinner when Brian, who (contrivance alert) plays basketball with Jackson, tries to set him up with Valerie — unaware that they already know each other.

Ms. Diamond, the author of “Stick Fly,” seen briefly on Broadway, can write sharply funny dialogue: Noting Valerie’s corseted costumes, Jackson assumes she is “one of those weird medieval fair people,” and adds that, “I didn’t think we did those.” (“We” being black people.) When Valerie tells him she’s in a Shakespeare production, he shoots back with a laugh, “I didn’t think our people did that either.”

But in airing thorny debates over Brian’s theories of genetic predisposition to racism, the script is stuffed with academic and psychiatric jargon (“The stereotype-content model predicts differentiated variables”) and the characters often seem to be mere receptacles for the ideas they espouse rather than fully fleshed-out people.

Although Ms. Diamond is clearly herself a powerfully smart writer, you come away from “Smart People” feeling like you’ve attended a marathon series of seminars, not a persuasively drawn drama.